Through Focus Retinal Image Capturing

ABSTRACT

An apparatus for producing a non-mydriatic fundus image is disclosed. The apparatus can include a processor and memory, as well as an illumination component and a camera with a variable focus lens. The apparatus can be configured to adjust the focus of the lens to a plurality of different diopter ranges and capture at least one image at each of the plurality of different diopter ranges. A method for capturing a non-mydriatic image of a fundus is also disclosed. The method can include setting a depth of field, dividing the depth of field into a plurality of zones, adjusting a variable focus lens of a camera to focus on each of the plurality of zones, and capturing at least one image at each of the plurality of zones.

INTRODUCTION

People with type 1 or type 2 diabetes can develop eye disease as aresult of having diabetes. One of the most common diabetic eye diseasesis diabetic retinopathy, which is damage to the blood vessels of thelight-sensitive tissue at the back of the eye, known as the retina.Trained medical professionals use cameras during eye examinations fordiabetic retinopathy screening. The cameras can produce images of theback of the eye and trained medical professionals use those images todiagnose and treat diabetic retinopathy.

These images are produced either with pharmacological pupil dilation,known as mydriatic fundus imaging, or without pharmacological pupildilation, known as non-mydriatic fundus imaging. Because pupil dilationis inversely related, in part, to the amount of ambient light,non-mydriatic fundus imaging usually occurs in low lightingenvironments. Medical professionals can also use fundus imagingapparatus to detect or monitor other diseases, such as hypertension,glaucoma, and papilledema.

SUMMARY

In one aspect, an apparatus for producing a non-mydriatic fundus imageis disclosed. The apparatus can include a processor and memory, a lightsource, and a camera including a variable focus lens. The memory canstore instructions that, when executed by the processor, cause theapparatus to adjust the focus of the lens to a plurality of differentdiopter ranges and capture a plurality of images of the fundus, wherethe camera captures at least one image at each of the different diopterranges.

In another aspect, a method for capturing a non-mydriatic image of afundus is disclosed. The method can include dividing a depth of fieldinto a plurality of zones, adjusting a lens of a camera to focus on eachof the plurality of zones and capturing at least one image at each ofthe plurality of zones.

In another aspect, a non-mydriatic image capture system is disclosed.The system can include a housing, an image capture device coupled to thehousing and configured to capture images of an eye fundus of a subject,and a control module programmed to: instruct the image capture device tocapture a plurality of images in a first image capture mode, process atleast a portion of the plurality of images to determine a position of apupil of the subject, and instruct the image capture device to capturean image in a second image capture mode when the position of the pupilis substantially aligned with an optical axis of the image capturedevice. The second image capture mode includes an illumination of alight source and a plurality of adjustments of a lens of the imagecapture device such that the image capture device captures an image ateach of the plurality of adjustments in a depth of field focus range.

DESCRIPTION OF THE FIGURES

The following figures, which form a part of this application, areillustrative of described technology and are not meant to limit thescope of the claims in any manner, which scope shall be based on theclaims appended hereto.

FIG. 1 is an embodiment of an example system for recording and viewingan image of a patient's fundus;

FIG. 2 is an embodiment of an example fundus imaging system;

FIG. 3 is an embodiment of an example method for imaging a patient'sfundus using a fundus imaging system;

FIG. 4 is an embodiment of an example fundus imaging system;

FIG. 5 illustrates an example method of initiating a fundus imagingusing passive eye tracking;

FIG. 6 is an embodiment of an example use of a fundus imaging system;and

FIG. 7 is an example computing device used within the fundus imagingsystem.

DETAILED DESCRIPTION

FIG. 1 is a schematic block diagram illustrating an example system 100for recording and viewing an image of a patient's fundus. In thisexample, the system 100 includes a patient P, a fundus imaging system102, a computing device 1800 including an image processor 106, a camera104 in communication with the computing device 1800, a display 108 incommunication with the computing device 1800 and used by clinician C,and a network 110. An embodiment of the example fundus imaging system102 is shown and described in more detail below with reference to FIG.4.

The fundus imaging system 102 functions to create a set of digital imageof a patient's P eye fundus. As used herein, “fundus” refers to the eyefundus and includes the retina, optic nerve, macula, vitreous, choroidand posterior pole.

In this example, one or more images of the eye are desired. Forinstance, the patient P is being screened for an eye disease, such asdiabetic retinopathy. The fundus imaging system 102 can also be used toprovide images of the eye for other purposes, such as to diagnose ormonitor the progression of a disease such as diabetic retinopathy.

The fundus imaging system 102 includes a handheld housing that supportsthe system's components. The housing supports one or two apertures forimaging one or two eyes at a time. In embodiments, the housing supportspositional guides for the patient P, such as an optional adjustable chinrest. The positional guide or guides help to align the patient's P eyeor eyes with the one or two apertures. In embodiments, the housingsupports means for raising and lowering the one or more apertures toalign them with the patient's P eye or eyes. Once the patient's P eyesare aligned, the clinician C then initiates the image captures by thefundus imaging system 102.

One technique for fundus imaging requires mydriasis, or the dilation ofthe patient's pupil, which can be painful and/or inconvenient to thepatient P. Example system 100 does not require a mydriatic drug to beadministered to the patient P before imaging, although the system 100can image the fundus if a mydriatic drug has been administered.

The system 100 can be used to assist the clinician C in screening for,monitoring, or diagnosing various eye diseases, such as hypertension,diabetic retinopathy, glaucoma and papilledema. It will be appreciatedthat the clinician C that operates the fundus imaging system 102 can bedifferent from the clinician C evaluating the resulting image.

In the example embodiment 100, the fundus imaging system 102 includes acamera 104 in communication with an image processor 106. In thisembodiment, the camera 104 is a digital camera including a lens, anaperture, and a sensor array. The camera 104 lens is a variable focuslens, such as a lens moved by a step motor, or a fluid lens, also knownas a liquid lens in the art. The camera 104 is configured to recordimages of the fundus one eye at a time. In other embodiments, the camera104 is configured to record an image of both eyes substantiallysimultaneously. In those embodiments, the fundus imaging system 102 caninclude two separate cameras, one for each eye.

In example system 100, the image processor 106 is operatively coupled tothe camera 104 and configured to communicate with the network 110 anddisplay 108.

The image processor 106 regulates the operation of the camera 104.Components of an example computing device, including an image processor,are shown in more detail in FIG. 7, which is described further below.

The display 108 is in communication with the image processor 106. In theexample embodiment, the housing supports the display 108. In otherembodiments, the display connects to the image processor, such as asmart phone, tablet computer, or external monitor. The display 108functions to reproduce the images produced by the fundus imaging system102 in a size and format readable by the clinician C. For example, thedisplay 108 can be a liquid crystal display (LCD) and active matrixorganic light emitting diode (AMOLED) display. The display can be touchsensitive.

The example fundus imaging system 102 is connected to a network 110. Thenetwork 110 may include any type of wireless network, a wired network,or any communication network known in the art. For example, wirelessconnections can include cellular network connections and connectionsmade using protocols such as 802.11a, b, and/or g. In other examples, awireless connection can be accomplished directly between the fundusimaging system 102 and an external display using one or more wired orwireless protocols, such as Bluetooth, Wi-Fi Direct, radio-frequencyidentification (RFID), or Zigbee. Other configurations are possible.

FIG. 2 illustrates components of an example fundus imaging system 102.The example fundus imaging system 102 includes a variable focus lens180, an illumination LED 182, an image sensor array 186, a fixation LED184, a computing device 1800, and a display 108. Each component is inelectrical communication with, at least, the computing device 1800.Other embodiments can include more or fewer components.

In one of the embodiments, the variable focus lens 180 is a liquid lens.A liquid lens is an optical lens whose focal length can be controlled bythe application of an external force, such as a voltage. The lensincludes a transparent fluid, such as water or water and oil, sealedwithin a cell and a transparent membrane. By applying a force to thefluid, the curvature of the fluid changes, thereby changing the focallength. This effect is known as electrowetting.

Generally, a liquid lens can focus between about −10 diopters to about+30 diopters. The focus of a liquid lens can be made quickly, even withlarge changes in focus. For instance, some liquid lenses can autofocusin tens of milliseconds or faster. Liquid lenses can focus from about 10cm to infinity and can have an effective focal length of about 16 mm orshorter.

In another embodiment of example fundus imaging system 102, the variablefocus lens 180 is one or more movable lenses that are controlled by astepping motor, a voice coil, an ultrasonic motor, or a piezoelectricactuator. Additionally, a stepping motor can also move the image sensorarray 186. In those embodiments, the variable focus lens 180 and/or theimage sensor array 186 are oriented normal to an optical axis of thefundus imaging system 102 and move along the optical axis. An examplestepping motor is shown and described below with reference to FIG. 4.

The example fundus imaging system 102 also includes an illuminationlight-emitting diode (LED) 182. The illumination LED 182 can be singlecolor or multi-color. For example, the illumination LED 182 can be athree-channel RGB LED, where each die is capable of independent andtandem operation.

Optionally, the illumination LED 182 is an assembly including one ormore visible light LEDs and a near-infrared LED. The optionalnear-infrared LED can be used in a preview mode, for example, for theclinician C to determine or estimate the patient's P eye focus withoutilluminating visible light that could cause the pupil to contract orirritate the patient P.

The illumination LED 182 is in electrical communication with thecomputing device 1800. Thus, the illumination of illumination LED 182 iscoordinated with the adjustment of the variable focus lens 180 and imagecapture. The illumination LED 182 can be overdriven to draw more thanthe maximum standard current draw rating. In other embodiments, theillumination LED 182 can also include a near-infrared LED. Thenear-infrared LED is illuminated during a preview mode.

The example fundus imaging system 102 also optionally includes afixation LED 184. The fixation LED 184 is in communication with thecomputing device 1800 and produces a light to guide the patient's P eyefor alignment. The fixation LED 184 can be a single color or multicolorLED. For example, the fixation LED 184 can produce a beam of green lightthat appears as a green dot when the patient P looks into the fundusimaging system 102. Other colors and designs, such as a cross, “x” andcircle are possible.

The example fundus imaging system 102 also includes an image sensorarray 186 that receives and processes light reflected by the patient'sfundus. The image sensor array 186 is, for example, a complementarymetal-oxide semiconductor (CMOS) sensor array, also known as an activepixel sensor (APS), or a charge coupled device (CCD) sensor.

The image sensor array 186 has a plurality of rows of pixels and aplurality of columns of pixels. In some embodiments, the image sensorarray has about 1280 by 1024 pixels, about 640 by 480 pixels, about 1500by 1152 pixels, about 2048 by 1536 pixels, or about 2560 by 1920 pixels.

In some embodiments, the pixel size in the image sensor array 186 isfrom about four micrometers by about four micrometers; from about twomicrometers by about two micrometers; from about six micrometers byabout six micrometers; or from about one micrometer by about onemicrometer.

The example image sensor array 186 includes photodiodes that have alight-receiving surface and have substantially uniform length and width.During exposure, the photodiodes convert the incident light to a charge.The image sensor array 186 can be operated as a global reset, that is,substantially all of the photodiodes are exposed simultaneously and forsubstantially identical lengths of time.

The example fundus imaging system 102 also includes a display 108,discussed in more detail above with reference to FIG. 1. Additionally,the example fundus imaging system 102 includes a computing device 1800,discussed in more detail below with reference to FIG. 7.

FIG. 3 is an embodiment of a method 200 for imaging a patient's fundususing a fundus imaging system. In the embodiment shown, the lighting isoptimally dimmed prior to execution, although lowering the lighting isoptional. The embodiment shown includes a set depth of field operation204, a set number of zones operation 206, an illuminate lightingoperation 208, an adjust lens focus operation 210, a capture imageoperation 212, repeat operation(s) 213, a show images operation 214 anda determine representative image operation 216. Other embodiments caninclude more or fewer steps.

The embodiment of method 200 begins with setting a depth of fieldoperation 204. In embodiments, the variable focus lens 180 is capable offocusing from about −20 diopters to about +20 diopters. Set depth offield operation 204 defines the lower and upper bounds in terms ofdiopters. For example, the depth of field range could be set to about−10 to +10 diopters; about −5 to about +5 diopters; about −10 to about+20 diopters; about −5 to about +20 diopters; about −20 to about +0diopters; or about −5 to about +5 diopters. Other settings are possible.The depth of field can be preprogrammed by the manufacturer.Alternatively, the end user, such as the clinician C, can set the depthof field.

As shown in FIG. 3, the next operation in embodiment of method 200 issetting the number of zones operation 206. However, zones operation 206can occur before or concurrent with field operation 204. In zonesoperation 206, the depth of field is divided into equal parts, whereeach part is called a zone. In other embodiments, the zones are not allequal. The number of zones is equal to the number of images captured incapture image operation 212.

For example, when the depth of field is from −10 to +10 diopters, thefocus of the variable focus lens can be changed by 4 diopters beforeeach image capture. Thus, in this example, images would be captured at−10, −6, −2, +2, +6 and +10 diopters. Or, images could be captured at−8, −4, 0, +4 and +8 diopters, thereby capturing an image in zones −10to −6 diopters, −6 to −2 diopters, −2 to +2 diopters, +2 to +6 dioptersand +6 to +10 diopters, respectively. In that instance, the depth offocus is about +/−2 diopters. Of course, the number of zones and thedepth of field can vary, resulting in different ranges of depth of fieldimage capture.

In embodiments, both depth of field and number of zones arepredetermined. For example, −10D to +10D and 5 zones. Both can bechanged by a user.

After the depth of field and number of zones are set, the next operationin embodiment of method 200 is the image capture process, which includesilluminate lighting operation 208, adjust lens focus operation 210 andcapture image operation 212. As shown in FIG. 3, the lighting componentis illuminated (lighting operation 208) before the lens focus isadjusted (lens focus operation 210). However, lens focus operation 210can occur before or concurrent with lighting operation 208.

The illumination LED 182 is illuminated in lighting operation 208. Theillumination LED 182 can remain illuminated throughout the duration ofeach image capture. Alternatively, the illumination LED 182 can beturned on and off for each image capture. In embodiments, theillumination LED 182 only turns on for the same period of time as theimage sensor array 186 exposure time period.

Optionally, lighting operation 208 can additionally include illuminatinga near-infrared LED. The clinician C can use the illumination of thenear-infrared LED as a way to preview the position of the patient's Ppupil.

The focus of variable focus lens 180 is adjusted in lens focus operation210. Autofocusing is not used in embodiment of method 200. That is, thediopter setting is provided to the lens without regard to the quality ofthe focus of the image. Indeed, traditional autofocusing fails in thelow-lighting non-mydriatic image capturing environment. The embodimentof method 200 results in a plurality of images at least one of which, ora combination of which, yields an in-focus view of the patient's Pfundus.

Additionally, the lack of autofocusing enables the fundus imaging system102 to rapidly capture multiple images in capture image operation 212 atdifferent diopter ranges. That is, variable focus lens 180 can be set toa particular diopter range and an image captured without the systemverifying that the particular focus level will produce an in-focusimage, as is found in autofocusing systems. Because the system does notattempt to autofocus, and the focus of the variable focus lens 180 canbe altered in roughly tens of milliseconds, images can be capturedthroughout the depth of field in well under a second, in embodiments.Thus, in the embodiment of method 200, the fundus imaging system 102 cancapture images of the entire depth of field before the patient's P eyecan react to the illuminated light. Without being bound to a particulartheory, depending on the patient P, the eye might react to the lightfrom illumination LED 182 in about 150 milliseconds.

The image sensor array 186 captures an image of the fundus in captureimage operation 212. As discussed above, the embodiment of method 200includes multiple image captures of the same fundus at different diopterfoci. The example fundus imaging system 102 uses a global reset orglobal shutter array, although other types of shutter arrays, such as arolling shutter, can be used. The entire image capture method 200 canalso be triggered by passive eye tracking and automatically capture, forexample, 5 frames of images. An embodiment of example method for passiveeye tracking is shown and described in more detail with reference toFIG. 5, below.

After the fundus imaging system 102 captures an image of the fundus, theembodiment of method 200 returns in loop 213 to either the illuminatelighting operation 208 or the adjust lens focus operation 210. That is,operations 208, 210 and 212 are repeated until an image is captured ineach of the preset zones from zones operation 206. It is noted that theimage capture does not need to be sequential through the depth of field.Additionally, each of the images does not need to be captured in asingle loop; a patient could have one or more fundus images captured andthen one or more after a pause or break.

After an image is captured in each of the zones (capture image operation212) in embodiment of method 200, either the images are displayed inshow images operation 214 or a representative image is determined inoperation 216 and then the image is displayed. Show images operation 214can include showing all images simultaneously or sequentially on display108. A user interface shown on display 108 can then enable the clinicianC or other reviewing medical professional to select or identify the bestor a representative image of the patient's P fundus.

In addition to, or in place of, show images operation 214, the computingdevice can determine a representative fundus image in operation 216.Operation 216 can also produce a single image by compiling aspects ofone or more of the images captured. This can be accomplished by, forexample, using a wavelet feature reconstruction method to select,interpolate, and/or synthesize the most representative frequency orlocation components.

The fundus imaging system 102 can also produce a three-dimensional imageof the fundus by compiling the multiple captured images. Because theimages are taken at different focus ranges of the fundus, thecompilation of the pictures can contain three-dimensional informationabout the fundus.

In turn, the image or images from operation 214 or 216 can be sent to apatient's electronic medical record or to a different medicalprofessional via network 110.

FIG. 4 illustrates an embodiment of example fundus imaging system 400.The embodiment 400 includes a housing 401 that supports an optionalfixation LED 402, an objective lens 404, fixation LED mirrors 405,variable focus lens assembly 406, display 408, printed circuit board410, step motor 412, image sensor array 414, and illumination LED 416.Also shown in FIG. 4 are light paths L that include potential lightpaths from optional fixation LED 402 and incoming light paths fromoutside the fundus imaging system 400. The illustrated components havethe same or similar functionality to the corresponding componentsdiscussed above with reference to FIGS. 1-3 above. Other embodiments caninclude more or fewer components.

The housing 401 of example fundus imaging system 400 is sized to be handheld. In embodiments, the housing 401 additionally supports one or moreuser input buttons near display 408, not shown in FIG. 4. The user inputbutton can initiate the image capture sequence, at least a portion ofwhich is shown and discussed with reference to FIG. 3, above. Thus, thefundus imaging system 400 is capable of being configured such that theclinician C does not need to adjust the lens focus.

Fixation LED 402 is an optional component of the fundus imaging system400. The fixation LED 402 is a single or multi-colored LED. Fixation LED402 can be more than one LED.

As shown in FIG. 4, pivoting mirrors 405 can be used to direct lightfrom the fixation LED 402 towards the patient's pupil. Additionally, anoverlay or filter can be used to project a particular shape or image,such as an “X”, to direct the patient's focus. The pivoting mirrors 405can control where the fixation image appears in the patient's view. Thepivoting mirrors 405 do not affect the light reflected from thepatient's fundus.

The embodiment of example fundus imaging system 400 also includes avariable focus lens assembly 406. As shown in FIG. 4, the variable focuslens assembly 406 is substantially aligned with the longitudinal axis ofthe housing 401. Additionally, the variable focus lens assembly 406 ispositioned between the objective lens 404 and the image sensor array 414such that it can control the focus of the incident light L onto theimage sensor array.

The example printed circuit board 410 is shown positioned within onedistal end of the housing 401 near the display 408. However, the printedcircuit board 410 can be positioned in a different location. The printedcircuit board 410 supports the components of the example computingdevice 1800. A power supply can also be positioned near printed circuitboard 410 and configured to power the components of the embodiment ofexample fundus imaging system 400.

Step motor 412 is an optional component in the example embodiment 400.Step motor 412 can also be, for example, a voice coil, an ultrasonicmotor, or a piezoelectric actuator. In the example embodiment 400, stepmotor 412 moves the variable focus lens assembly 406 and/or the sensorarray 414 to achieve variable focus. The step motor 412 moves thevariable focus lens assembly 406 or the sensor array 414 in a directionparallel to a longitudinal axis of the housing 401 (the optical axis).The movement of step motor 412 is actuated by computing device 1800.

The example image sensor array 414 is positioned normal to thelongitudinal axis of the housing 401. As discussed above, the imagesensor array 414 is in electrical communication with the computingdevice. Also, as discussed above, the image sensor array can be a CMOS(APS) or CCD sensor.

An illumination LED 416 is positioned near the variable focus lensassembly 406. However, the illumination LED 416 can be positioned inother locations, such as near or with the fixation LED 402.

FIG. 5 illustrates an alternate embodiment of initiate retinal imagingstep 306 using passive eye tracking The initiate retinal imaging step306 operates to image the fundus of the patient P using passive eyetracking. In the initiate retinal imaging step 306, the fundus imagingsystem 102 monitors the pupil/fovea orientation of the patient P.Although the initiate retinal imaging step 306 is described with respectto fundus imaging system 102, the initiate retinal imaging step 306 maybe performed using a wearable or nonwearable fundus imaging system, suchas a handheld digital fundus imaging system.

Initially, at step 303, the pupil or fovea or both of the patient P aremonitored. The fundus imaging system 102 captures images in a firstimage capture mode. In the first image capture mode, the fundus imagingsystem 102 captures images at a higher frame rate. In some embodiments,in the first image capture mode, the fundus imaging system 102 capturesimages with infra-red illumination and at lower resolutions. In someembodiments, the infra-red illumination is created by the illuminationLED 182 operating to generate and direct light of a lower intensitytowards the subject. The first image capture mode may minimizediscomfort to the patient P, allow the patient P to relax, and allow fora larger pupil size without dilation (non-mydriatic).

Next, at step 305, the computing system 1800 processes at least aportion of the images captured by the fundus imaging system 102. Thecomputing system 1800 processes the images to identify the location ofthe pupil or fovea or both of the patient P. Using the location of thepupil or fovea or both in one of the images, a vector corresponding tothe pupil/fovea orientation is calculated. In some embodiments, thepupil/fovea orientation is approximated based on the distance betweenthe pupil and fovea in the image. In other embodiments, the pupil/foveaorientation is calculated by approximating the position of the fovearelative to the pupil in three dimensions using estimates of thedistance to the pupil and the distance between the pupil and the fovea.In other embodiments, the pupil/fovea orientation is approximated fromthe position of the pupil alone. In yet other embodiments, other methodsof approximating the pupil/fovea orientation are used.

Next, at step 307, the pupil/fovea orientation is compared to theoptical axis of the fundus imaging system 102. If the pupil/foveaorientation is substantially aligned with the optical axis of the fundusimaging system 102, the process proceeds to step 309 to capture a fundusimage. If not, the process returns to step 303 to continue to monitorthe pupil or fovea. In some embodiments, the pupil/fovea orientation issubstantially aligned with the optical axis when the angle between themis less than two to fifteen degrees.

Next, at step 309, fundus images are captured by triggering theembodiment of example thru focusing image capturing method 200. Inembodiments, five images are captured at step 309. In some embodiments,the fundus image is captured in a second image capture mode. In someembodiments, in the second image capture mode, the fundus imaging system102 captures images with visible illumination and at higher resolutions.In some embodiments, the visible illumination is created by theillumination LED 182 operating to generate and direct light of a higherintensity towards the subject. In other embodiments, the higherillumination is created by an external light source or ambient light.The second image capture mode may facilitate capturing a clear,well-illuminated, and detailed fundus image.

In some embodiments, after step 309, the initiate retinal imaging step306 returns to step 303 to continue to monitor the pupil/foveaorientation. The initiate retinal imaging step 306 may continue tocollect fundus images indefinitely or until a specified number of imageshave been collected. Further information regarding passive eye trackingcan be found in U.S. patent application Ser. No. 14/177,594, attorneydocket number 10156.0082US01, titled Ophthalmoscope Device, which ishereby incorporated by reference in its entirety

FIG. 6 is an embodiment of example use 500 of fundus imaging system 102.In the embodiment of example use 500, a clinician positions the fundusimaging system (operation 502), initiates image capture (operation 504),positions the fundus imaging system over the other eye (operation 506),initiates image capture (operation 508), and views images (operation520). Although the example use 500 is conducted without firstadministering mydriatic pharmaceuticals, the example use 500 can also beperformed for a patient who has taken a pupil-dilating compound. Theembodiment of example use 500 can also include lowering the lighting.The embodiment of example use 500 is conducted using the same or similarcomponents as those described above with reference to FIGS. 1-3. Otherembodiments can include more or fewer operations.

The embodiment of example use 500 begins by positioning the fundusimaging system (operation 502). In embodiments, the clinician firstinitiates an image capture sequence via a button on the housing or agraphical user interface shown by the display. The graphical userinterface can instruct the clinician to position the fundus imagingsystem over a particular eye of the patient. Alternatively, theclinician can use the graphical user interface to indicate which eyefundus is being imaged first.

In operation 502, the clinician positions the fundus imaging system nearthe patient's eye socket. The clinician positions the aperture of thesystem flush against the patient's eye socket such that the aperture, ora soft material eye cup extending from the aperture, seals out most ofthe ambient light. Of course, the example use 500 does not requirepositioning the aperture flush against the patient's eye socket.

When the fundus imaging system is in position, the system captures morethan one image of the fundus in operation 504. As discussed above, thesystem does not require the clinician to manually focus the lens.Additionally, the system does not attempt to autofocus on the fundus.Rather, the clinician simply initiates the image capture, via a buttonor the GUI, and the fundus imaging system controls when to capture theimages and the focus of the variable focus lens. Also, as discussedabove at least with reference to FIG. 5, the system can initiate imagecapture using passive eye tracking

The patient may require the fundus imaging system to be moved away fromthe eye socket during image capture operation 504. The clinician canre-initiate the image capture sequence of the same eye using the buttonor the GUI on the display.

After capturing an image in each of the specified zones, the fundusimaging system notifies the clinician that the housing should bepositioned over the other eye (operation 506). The notification can beaudible, such as a beep, and/or the display can show a notification. Inembodiments, the system is configured to capture a set of images of onlyone eye, wherein the example method 500 proceeds to view imagesoperation 520 after image capture operation 504.

Similar to operation 502, the clinician then positions the fundusimaging system near or flush with the patient's other eye socket inoperation 506. Again, when the system is in place, an image is capturedin every zone in operation 508.

After images have been captured of the fundus in each pre-set zone, theclinician can view the resulting images in operation 520. As noted abovewith reference to FIG. 3, the images can be post-processed before theclinician views the images to select or synthesize a representativeimage. Additionally, the fundus images can be sent to a remote locationfor viewing by a different medical professional.

FIG. 7 is a block diagram illustrating physical components (i.e.,hardware) of a computing device 1800 with which embodiments of thedisclosure may be practiced. The computing device components describedbelow may be suitable to act as the computing devices described above,such as wireless computing device and/or medical device of FIG. 1. In abasic configuration, the computing device 1800 may include at least oneprocessing unit 1802 and a system memory 1804. Depending on theconfiguration and type of computing device, the system memory 1804 maycomprise, but is not limited to, volatile storage (e.g., random accessmemory), non-volatile storage (e.g., read-only memory), flash memory, orany combination of such memories. The system memory 1804 may include anoperating system 1805 and one or more program modules 1806 suitable forrunning software applications 1820. The operating system 1805, forexample, may be suitable for controlling the operation of the computingdevice 1800. Furthermore, embodiments of the disclosure may be practicedin conjunction with a graphics library, other operating systems, or anyother application program and is not limited to any particularapplication or system. This basic configuration is illustrated in FIG. 7by those components within a dashed line 1808. The computing device 1800may have additional features or functionality. For example, thecomputing device 1800 may also include additional data storage devices(removable and/or non-removable) such as, for example, magnetic disks,optical disks, or tape. Such additional storage is illustrated in FIG. 7by a removable storage device 1809 and a non-removable storage device1810.

As stated above, a number of program modules and data files may bestored in the system memory 1804. While executing on the processing unit1802, the program modules 1806 may perform processes including, but notlimited to, generate list of devices, broadcast user-friendly name,broadcast transmitter power, determine proximity of wireless computingdevice, connect with wireless computing device, transfer vital sign datato a patient's EMR, sort list of wireless computing devices withinrange, and other processes described with reference to the figures asdescribed herein. Other program modules that may be used in accordancewith embodiments of the present disclosure, and in particular togenerate screen content, may include electronic mail and contactsapplications, word processing applications, spreadsheet applications,database applications, slide presentation applications, drawing orcomputer-aided application programs, etc.

Furthermore, embodiments of the disclosure may be practiced in anelectrical circuit comprising discrete electronic elements, packaged orintegrated electronic chips containing logic gates, a circuit utilizinga microprocessor, or on a single chip containing electronic elements ormicroprocessors. For example, embodiments of the disclosure may bepracticed via a system-on-a-chip (SOC) where each or many of thecomponents illustrated in FIG. 7 may be integrated onto a singleintegrated circuit. Such an SOC device may include one or moreprocessing units, graphics units, communications units, systemvirtualization units and various application functionality all of whichare integrated (or “burned”) onto the chip substrate as a singleintegrated circuit. When operating via an SOC, the functionality,described herein, may be operated via application-specific logicintegrated with other components of the computing device 1800 on thesingle integrated circuit (chip). Embodiments of the disclosure may alsobe practiced using other technologies capable of performing logicaloperations such as, for example, AND, OR, and NOT, including but notlimited to mechanical, optical, fluidic, and quantum technologies. Inaddition, embodiments of the disclosure may be practiced within ageneral purpose computer or in any other circuits or systems.

The computing device 1800 may also have one or more input device(s) 1812such as a keyboard, a mouse, a pen, a sound or voice input device, atouch or swipe input device, etc. The output device(s) 1814 such as adisplay, speakers, a printer, etc. may also be included. Theaforementioned devices are examples and others may be used. Thecomputing device 1800 may include one or more communication connections1816 allowing communications with other computing devices. Examples ofsuitable communication connections 1816 include, but are not limited to,RF transmitter, receiver, and/or transceiver circuitry; universal serialbus (USB), parallel, and/or serial ports.

The term computer readable media as used herein may includenon-transitory computer storage media. Computer storage media mayinclude volatile and nonvolatile, removable and non-removable mediaimplemented in any method or technology for storage of information, suchas computer readable instructions, data structures, or program modules.The system memory 1804, the removable storage device 1809, and thenon-removable storage device 1810 are all computer storage mediaexamples (i.e., memory storage.) Computer storage media may include RAM,ROM, electrically erasable read-only memory (EEPROM), flash memory orother memory technology, CD-ROM, digital versatile disks (DVD) or otheroptical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or any other article ofmanufacture which can be used to store information and which can beaccessed by the computing device 1800. Any such computer storage mediamay be part of the computing device 1800. Computer storage media doesnot include a carrier wave or other propagated or modulated data signal.

Communication media may be embodied by computer readable instructions,data structures, program modules, or other data in a modulated datasignal, such as a carrier wave or other transport mechanism, andincludes any information delivery media. The term “modulated datasignal” may describe a signal that has one or more characteristics setor changed in such a manner as to encode information in the signal. Byway of example, and not limitation, communication media may includewired media such as a wired network or direct-wired connection, andwireless media such as acoustic, radio frequency (RF), infrared, andother wireless media.

Although the example medical devices described herein are devices usedto monitor patients, other types of medical devices can also be used.For example, the different components of the CONNEX™ system, such as theintermediary servers that communication with the monitoring devices, canalso require maintenance in the form of firmware and software updates.These intermediary servers can be managed by the systems and methodsdescribed herein to update the maintenance requirements of the servers.

Embodiments of the present invention may be utilized in variousdistributed computing environments where tasks are performed by remoteprocessing devices that are linked through a communications network in adistributed computing environment.

The block diagrams depicted herein are just examples. There may be manyvariations to these diagrams described therein without departing fromthe spirit of the disclosure. For instance, components may be added,deleted or modified.

While embodiments have been described, it will be understood that thoseskilled in the art, both now and in the future, may make variousimprovements and enhancements can be made.

As used herein, “about” refers to a degree of deviation based onexperimental error typical for the particular property identified. Thelatitude provided the term “about” will depend on the specific contextand particular property and can be readily discerned by those skilled inthe art. The term “about” is not intended to either expand or limit thedegree of equivalents which may otherwise be afforded a particularvalue. Further, unless otherwise stated, the term “about” shallexpressly include “exactly,” consistent with the discussions regardingranges and numerical data. Concentrations, amounts, and other numericaldata may be expressed or presented herein in a range format. It is to beunderstood that such a range format is used merely for convenience andbrevity and thus should be interpreted flexibly to include not only thenumerical values explicitly recited as the limits of the range, but alsoto include all the individual numerical values or sub-ranges encompassedwithin that range as if each numerical value and sub-range is explicitlyrecited. As an illustration, a numerical range of “about 4 percent toabout 7 percent” should be interpreted to include not only theexplicitly recited values of about 4 percent to about 7 percent, butalso include individual values and sub-ranges within the indicatedrange. Thus, included in this numerical range are individual values suchas 4.5, 5.25 and 6 and sub-ranges such as from 4-5, from 5-7, and from5.5-6.5; etc. This same principle applies to ranges reciting only onenumerical value. Furthermore, such an interpretation should applyregardless of the breadth of the range or the characteristics beingdescribed.

The description and illustration of one or more embodiments provided inthis application are not intended to limit or restrict the scope of theinvention as claimed in any way. The embodiments, examples, and detailsprovided in this application are considered sufficient to conveypossession and enable others to make and use the best mode of claimedinvention. The claimed invention should not be construed as beinglimited to any embodiment, example, or detail provided in thisapplication. Regardless whether shown and described in combination orseparately, the various features (both structural and methodological)are intended to be selectively included or omitted to produce anembodiment with a particular set of features. Having been provided withthe description and illustration of the present application, one skilledin the art may envision variations, modifications, and alternateembodiments falling within the spirit of the broader aspects of theclaimed invention and the general inventive concept embodied in thisapplication that do not depart from the broader scope.

What is claimed is:
 1. An apparatus for producing a non-mydriatic fundusimage, comprising: a processor and a memory; an illumination componentincluding a light source and operatively coupled to the processor; acamera including a lens and operatively coupled to the processor,wherein the memory stores instructions that, when executed by theprocessor, cause the apparatus to: adjust a focus of the lens to aplurality of different diopter ranges; and capture a plurality of imagesof a fundus, wherein the camera captures at least one image at each ofthe plurality of different diopter ranges.
 2. The apparatus of claim 1,wherein the instructions further cause the apparatus to: adjust thefocus of the lens and capture subsequent images until images have beencaptured of a depth of field from −10 diopters to +10 diopters.
 3. Theapparatus of claim 2, wherein each adjustment of the focus is by +/−1diopter.
 4. The apparatus of claim 2, wherein each adjustment of thefocus is by +/−2 diopters.
 5. The apparatus of claim 2, wherein theimages are captured sequentially in less than about 150 milliseconds. 6.The apparatus of claim 1, further comprising a visible light componentconfigured to illuminate during the capture of the plurality of images.7. The apparatus of claim 1, further comprising a display coupled to thememory and to the processor and configured to display a representativeimage of the fundus.
 8. A method for capturing a non-mydriatic image ofa fundus, comprising: dividing a depth of field into a plurality ofzones; adjusting a lens of a camera to focus on each of the plurality ofzones; and capturing at least one image at each of the plurality ofzones.
 9. The method of claim 8, wherein the depth of field is from −10diopters to +10 diopters.
 10. The method of claim 9, wherein the depthof field is divided into 5 equal zones.
 11. The method of claim 9,wherein the depth of field is divided into 10 zones.
 12. The method ofclaim 8, wherein a light source is illuminated throughout the capture ofeach image in each zone.
 13. The method of claim 8, further comprisingdetermining a representative image of the fundus from the plurality ofimages.
 14. A non-mydriatic imaging capture system, comprising: ahousing; an image capture device coupled to the housing and configuredto capture images of an eye fundus of a subject; and a control moduleprogrammed to: instruct the image capture device to capture a pluralityof images in a first image capture mode; process at least a portion ofthe plurality of images to determine a position of a pupil of thesubject; and instruct the image capture device to capture an image in asecond image capture mode when the position of the pupil issubstantially aligned with an optical axis of the image capture device,wherein the second image capture mode includes: an illumination of alight source; and a plurality of adjustments of a lens of the imagecapture device such that the image capture device captures an image ateach of the plurality of adjustments in a depth of field focus range.15. The system of claim 14, wherein the depth of field focus range isfrom −10 diopters to +10 diopters.
 16. The system of claim 15, furthercomprising a processor configured to determine an optimal image acquiredduring the second image capture mode.
 17. The system of claim 16,wherein the processor is further configured to construct athree-dimensional image using the images acquired during the secondimage capture mode.
 18. The system of claim 16, further comprising adisplay coupled to the processor and configured to display the optimalimage.
 19. The system of claim 14, wherein the position of the pupil issubstantially aligned with the optical axis of the image capture devicewhen an angle formed between the optical axis and a vector formedbetween the lens of the image capture device and the pupil is less thanfifteen degrees.
 20. The system of claim 14, wherein the second imagecapture mode occurs in a low light environment.